如何将以下foreach循环转换为linq代码格式？

Question

Code:

foreach (var testView in projectDataCandidate.ViewMaps
                                             .Where(vm => !vm.IsNotTestLane)
                                             .Select(this.GenerateTestView))
{
      this.SwimLaneViews.Add(testView);
      testView.ItemsOrphaned += OnItemsOrphaned;
}

How to write the above foreach loop in linq code format ? Thanks.

Answer 1

projectDataCandidate.ViewMaps
    .Where(vm => !vm.IsNotTestLane)
    .Select(this.GenerateTestView)
    .ToList()
    .ForEach(testView =>
    {
        this.SwimLaneViews.Add(testView);
        testView.ItemsOrphaned += OnItemsOrphaned;
    });

Answer 2

As others have already pointed out, you're already using LINQ for your query, and LINQ is for queries rather than commands.

Organise your logic

I think you're trying to improve the readability of your code. To do this, I suggest you extract out the query and command into different class members:

private IEnumerable<ViewMap> TestViews
{
    get
    {
        return projectDataCandidate.ViewMaps
            .Where(vm => !vm.IsNotTestLane)
            .Select(this.GenerateTestView);
    }
}

private void Process(ViewMap testView)
{
    this.SwimLaneViews.Add(testView);
    testView.ItemsOrphaned += OnItemsOrphaned;
}

Simplify your loop

Then your logic becomes the following, which is easy to read:

private void ProcessTestViews()
{
    foreach (var testView in TestViews)
        Process(testView);
}

Make your loop declarative

If you still don't like the look of the foreach , you could do this, which I think is even easier to read:

private void ProcessTestViews()
{
    TestViews.ToList().ForEach(Process);
}

Remove redundant ToList

If you don't want to convert the result to a List since it's not really needed, you could write an extension method to provide ForEach for IEnumerable<T> :

public static class IEnumerableExtensions
{
    public static void ForEach<T>(this IEnumerable<T> elements, Action<T> action)
    {
        foreach (var element in elements)
            action(element);
    }
}

This allows you to simplify your method a bit further:

private void ProcessTestViews()
{
    TestViews.ForEach(Process);
}

Answer 3

try

projectDataCandidate.ViewMaps.Where(vm => !vm.IsNotTestLane)
                                             .Select(this.GenerateTestView).ForEach(xx=>xx.Your logic)

Answer 4

The only way to do this that I can see is to force execution with a ToList, then use the ForEach function.

var objects = projectDataCandidate.ViewMaps
    .Where(vm => !vm.IsNotTestLane)
    .Select(this.GenerateTestView)
    .ToList();

objects.ForEach(a => SwimLaneViews.Add(a));
objects.ForEach(a => a.ItemsOrphaned += OnItemsOrphaned);